Dimensionality Effects in the Optics of Boron Nitride Nanostructures: Applications for Optoelectronic Devices

L. Wirtz, C. Attacalite, A. Marini, and A. Rubio

We illustrate the effect of dimensionality and electron-hole attraction in boron nitride (BN) compounds. The optical absorption spectra of BN nanotubes are dominated by strongly bound excitons. The absolute position of the first excitonic peak is almost independent of the tube radius and system dimensionality. This provides an explanation for the observed “optical gap” constancy for different tubes and bulk hexagonal BN. Furthermore, the levels which are responsible for defect-mediated photo-luminescence are shifted by the electric field making BN nanotubes excellent candidates for optoelectronic applications in the UV and below.